JP7450797B2 - Bumper caps and buffers - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to bumper caps and shock absorbers.
This application claims priority based on Japanese Patent Application No. 2021-027197 filed in Japan on February 24, 2021, the contents of which are incorporated herein.

In some shock absorbers, the side of the cylinder from which the rod protrudes is covered with a bumper cap (for example, see Patent Documents 1 and 2).

International Publication No. 2017/010254 Japanese Patent Application Publication No. 2016-061425

It is desired to suppress the generation of abnormal noise in a shock absorber.

Therefore, an object of the present invention is to provide a bumper cap and a shock absorber that can suppress the generation of abnormal noise.

In order to achieve the above object, one aspect of the bumper cap according to the present invention is a bumper cap that is attached to a shock absorber main body, one end having an opening, the other end having a bottom and a hole passing through the bottom. a cover part having a hole and covering the shock absorber main body; and a plurality of protrusions protruding from the bottom part of the cover part toward the opening side, with gaps being formed between adjacent protrusions. A suppressing portion is provided for suppressing rotation within the cover portion of fluid flowing from the outside of the cover portion through the through hole and flowing between the cover portion and the shock absorber main body.

Another aspect of the bumper cap according to the present invention is a bumper cap that is attached to a shock absorber main body, and has an opening at one end and a bottom and a through hole passing through the bottom at the other end. A cover part that covers the main body of the container, and a plurality of protrusion parts that protrude from the bottom part of the cover part toward the opening side and have gaps between adjacent ones, and are provided in the bottom part. The plurality of protruding parts are provided with inclined parts that face toward the inner diameter side of the bottom part and are inclined in the same direction with respect to the circumferential direction of the bottom part.

One aspect of the shock absorber according to the present invention is a shock absorber having a cylinder and a rod extending from one end side of the cylinder, and a through hole through which the rod is inserted is formed, and the one end side of the cylinder is formed with a through hole through which the rod is inserted. a plurality of protrusions protruding from the inner surface of the cover part at intervals in the circumferential direction of the cover part; and a plurality of protrusions protruding from the inner surface of the cover part at intervals, and a flow of water flowing from the outside of the cover part through the through hole and into the inside of the cover part. The present invention is configured to include a fluid adjustment unit that adjusts the velocity of the fluid that spreads outward in the circumferential direction of the through hole so that it varies depending on the circumferential position of the through hole.

According to the present invention, it is possible to suppress the generation of abnormal noise.

It is a sectional view showing a shock absorber of a 1st embodiment concerning the present invention. FIG. 2 is an enlarged sectional view of section II shown in FIG. 1 of the shock absorber according to the first embodiment of the present invention. FIG. 1 is a front view showing a bumper cap of a first embodiment according to the present invention. FIG. 1 is a perspective view showing a bumper cap according to a first embodiment of the present invention. It is a bottom view showing a bumper cap of a 1st embodiment concerning the present invention. It is a bottom view which shows the bumper cap of 2nd Embodiment based on this invention.

[First embodiment]
A first embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 shows a shock absorber according to a first embodiment. The shock absorber 1 of the first embodiment is a shock absorber used in a suspension device of a vehicle such as an automobile or a railway vehicle, and specifically, a shock absorber used in a strut type suspension of an automobile. The shock absorber 1 has a shock absorber main body 2 and a bumper cap 3.

The shock absorber main body 2 includes a cylindrical metal inner cylinder 12 and a bottomed cylinder that has a larger diameter than the inner cylinder 12 and is provided on the outer peripheral side of the inner cylinder 12 and forms a reservoir chamber 13 between the inner cylinder 12 and the inner cylinder 12. The main bracket 15 and the spring seat 16 are both fixed to the outer peripheral side of the outer cylinder 14 by welding. The inner tube 12 and the outer tube 14 constitute a cylindrical cylinder 17. The outer cylinder 14 has a cylindrical side wall 21 , a bottom 22 that closes one end of the side wall 21 in the axial direction, and an opening 23 of the side wall 21 on the opposite side of the bottom 22 .

The shock absorber main body 2 includes an annular metal body member 30 attached to one axial end of the inner cylinder 12 and an annular metal rod guide attached to the other axial end of the inner cylinder 12. It has 31. The inner cylinder 12 is engaged with the bottom 22 of the outer cylinder 14 via the body member 30, and is fitted into the opening 23 side of the side wall 21 of the outer cylinder 14 via the rod guide 31.

The shock absorber main body 2 has an annular seal member 32 on the opposite side of the bottom portion 22 with respect to the rod guide 31 . As shown in FIG. 2, the sealing member 32 is constructed by having an annular metal rigid member 34 embedded within an elastic member 33 made of rubber. The seal member 32 is fitted into the inner peripheral portion of the side wall portion 21 on the opening 23 side. The shock absorber main body 2 has an annular metal ring member 35 on the opening 23 side of the seal member 32 . A locking portion 36 that is plastically deformed radially inward by curling is formed at the end of the side wall portion 21 on the opening 23 side. It is held between this locking portion 36 and the rod guide 31 via a ring member 35.

As shown in FIG. 1, the shock absorber main body 2 has a piston 37 that is slidably fitted into the inner cylinder 12. The piston 37 defines a first chamber 38 and a second chamber 39 within the inner cylinder 12 . The first chamber 38 is provided between the piston 37 in the inner tube 12 and the rod guide 31, and the second chamber 39 is provided between the piston 37 in the inner tube 12 and the body member 30. The second chamber 39 is defined from the reservoir chamber 13 by the body member 30. The first chamber 38 and the second chamber 39 in the inner cylinder 12 are filled with oil, which is a working fluid, and the reservoir chamber 13 between the inner cylinder 12 and the outer cylinder 14 is filled with gas, which is a working fluid. It is filled with oil.

The shock absorber main body 2 has a metal cylindrical rod 41 connected to the piston 37 on one side and extending outward from the outer cylinder 14 through the opening 23 on the other side. Therefore, the rod 41 extends from one end side of the cylinder 17. The rod 41 is connected to the piston 37 by a nut 43, and moves together with the piston 37 relative to the cylinder 17. As shown in FIG. 2, the rod 41 extends from the cylinder 17 to the outside through the rod guide 31 and the elastic member 33 of the seal member 32. A portion of the rod 41 extending outward from the outer cylinder 14 is connected to the vehicle body. The rod 41 is guided by the rod guide 31 and moves in the axial direction with respect to the cylinder 17. The elastic member 33 closes the gap between the seal member 32 and the side wall portion 21, and the seal member 32 closes the gap between the seal member 32 and the rod 41. Therefore, the seal member 32 closes the space between the outer cylinder 14 and the rod 41 to prevent the oil in the inner cylinder 12 and the gas and oil in the reservoir chamber 13 from leaking to the outside.

As shown in FIG. 1, the piston 37 is formed with a passage 44 and a passage 45 that penetrate in the axial direction. The passages 44 and 45 allow the first chamber 38 and the second chamber 39 to communicate with each other. The shock absorber main body 2 has an annular disc valve 46 that can close the passage 44 by coming into contact with the piston 37 on the side opposite to the bottom 22 of the piston 37 . The shock absorber main body 2 also has an annular disc valve 47 on the bottom 22 side of the piston 37 that can close the passage 45 by coming into contact with the piston 37 .

In the disc valve 46, the rod 41 moves to the contraction side to increase the amount of penetration into the inner cylinder 12 and the outer cylinder 14, and the piston 37 moves in a direction to narrow the second chamber 39, so that the pressure in the second chamber 39 decreases to the first. When the pressure in the chamber 38 becomes higher than a predetermined value, the passage 44 is opened, and at that time, it is a compression-side damping valve that generates a damping force. At least one of the piston 37 and the disc valve 46 has a fixed orifice (not shown) that communicates the first chamber 38 and the second chamber 39 via the passage 44 even when the disc valve 46 is in the state where the passage 44 is most blocked. It is formed.

In the disc valve 47, the rod 41 moves to the extension side to increase the amount of protrusion from the inner cylinder 12 and the outer cylinder 14, and the piston 37 moves in a direction to narrow the first chamber 38, so that the pressure in the first chamber 38 is reduced to the second chamber. When the pressure becomes higher than the pressure of 39 by a predetermined value or more, the passage 45 is opened, and at that time, it is a damping valve on the extension side that generates a damping force. At least one of the piston 37 and the disc valve 47 has a fixed orifice (not shown) that communicates the first chamber 38 and the second chamber 39 via the passage 45 even when the disc valve 47 is in the state where the passage 45 is most blocked. It is formed.

A passage 52 and a passage 53 passing through the body member 30 in the axial direction are formed. The passages 52 and 53 allow the second chamber 39 and the reservoir chamber 13 to communicate with each other. The shock absorber main body 2 has an annular disc valve 55 on the bottom 22 side of the body member 30 that can close the passage 52 by coming into contact with the body member 30, and is opposite to the bottom 22 of the body member 30. It has an annular disc valve 56 on the side that can close the passage 53 by abutting against the body member 30.

The disc valve 55 opens the passage 52 when the rod 41 moves to the contraction side, the piston 37 moves in the direction to narrow the second chamber 39, and the pressure in the second chamber 39 becomes higher than the pressure in the reservoir chamber 13 by a predetermined value or more. This is the damping valve on the compression side that generates damping force at that time. The disc valve 56 opens the passage 53 when the rod 41 moves to the extension side, the piston 37 moves to the first chamber 38 side, and the pressure in the second chamber 39 becomes lower than the pressure in the reservoir chamber 13. This is a suction valve that allows the working liquid to flow from the reservoir chamber 13 into the second chamber 39 without substantially generating damping force.

The main bracket 15 is made of metal, and is fitted onto the side wall portion 21 on the bottom portion 22 side of the outer cylinder 14 from the axial center position and is fixed by welding. The main bracket 15 is connected to a wheel (not shown) using fasteners (not shown) inserted into the plurality of mounting holes 61 .

The spring seat 16 is made of metal, and is fitted into the side wall portion 21 on the side of the opening 23 with respect to the axial center position of the outer cylinder 14 and is fixed by welding. The spring seat 16 supports the lower end of a vehicle body support spring (not shown), which is a coil spring that supports the vehicle body (not shown).

As shown in FIG. 2, the bumper cap 3 is attached to the shock absorber body 2 so as to cover one end of the cylinder 17 from which the rod 41 projects. Here, the shock absorber body 2 has a seal member 32 at the outer end of the cylinder 17 on the side from which the rod 41 protrudes, and the bumper cap 3 protects this seal member 32. Specifically, the rod 41 is provided with a cylindrical bump rubber (not shown) on the outer circumferential side of the portion that protrudes outward from the seal member 32, and the cylinder 17 is provided with a bump rubber (not shown) at a distance from the vehicle body (not shown). When retracted, this bump rubber contacts the vehicle body and the bumper cap 3 and is elastically deformed to absorb the impact. At this time, the bumper cap 3 prevents the bump rubber from colliding with the seal member 32.

A bellows-shaped dust boot 65 extends downward from the vehicle body (not shown) so as to cover the portion of the rod 41 that protrudes outward from the sealing member 32 on the outer peripheral side. A lower end portion of this dust boot 65 is fixed to the bumper cap 3. The dust boot 65 covers at least a portion of the rod 41 on the outer circumferential side, and also covers the bump rubber (not shown) and the bumper cap 3 on the outer circumferential side. The above-mentioned vehicle body support spring (not shown) is arranged on the outer peripheral side of the dust boot 65.

The bumper cap 3 is an integrally molded product made of synthetic resin, and includes a cover portion 75 having a bottom portion 71, a body portion 72, a flange portion 73, and an outward convex portion 74, as shown in FIGS. 3 to 5. ing.

As shown in FIGS. 4 and 5, the bottom portion 71 is in the shape of a circular plate with a hole, and a through hole 81 that penetrates in the axial direction is formed at the center in the radial direction. The through hole 81 is a round hole with a circular cross section in a plane perpendicular to its central axis. In other words, in the bottom portion 71, the inner peripheral edge portion 82 forming the through hole 81 has a circular shape. As shown in FIG. 2, the inner circumferential edge portion 82 of the bottom portion 71 has an inner circumferential end surface 82a formed at one end in the axial direction of the bottom portion 71, and an inner circumferential end surface 82a at the other end in the axial direction of the bottom portion 71. A tapered surface 82b having a larger diameter than 82a is formed, and a step surface 82c connecting these is formed between them.

The inner circumferential end surface 82a has a cylindrical surface shape, and has the smallest diameter at the inner circumferential edge portion 82. The step surface 82c has a planar shape that extends radially outward from the end edge of the inner peripheral end surface 82a on the tapered surface 82b side in the axial direction. The tapered surface 82b extends from the outer peripheral edge of the stepped surface 82c in the axial direction on the opposite side to the inner peripheral end surface 82a, and becomes larger in diameter as it moves away from the inner peripheral end surface 82a. These inner circumferential end surface 82a, tapered surface 82b, and stepped surface 82c are coaxially formed and form a through hole 81.

The body portion 72 has a cylindrical shape and extends from the entire circumference of the outer peripheral edge of the bottom portion 71 to the side opposite to the inner peripheral end surface 82a in the axial direction of the bottom portion 71, coaxially with the bottom portion 71. The body portion 72 has an opening 78 on the side opposite to the bottom portion 71 in the axial direction. An inner surface 71a of the bottom part 71 on the side of the body part 72 in the axial direction has a planar shape that extends in a direction perpendicular to the axes of the bottom part 71 and the body part 72. The inner circumferential surface 72a of the body portion 72 has a cylindrical shape. The cover portion 75 has an opening 78 at one end, and a bottom portion 71 and a through hole 81 passing through the bottom portion 71 at the other end.

Here, the central axes of the through hole 81, the bottom part 71, and the body part 72, which are arranged coaxially, are the central axes of the bumper cap 3 and the cover part 75. Therefore, the through hole 81, the bottom portion 71, the body portion 72, the bumper cap 3, and the cover portion 75 are aligned in the axial direction, aligned in the circumferential direction, and aligned in the radial direction.

The flange portion 73 extends outward in the radial direction of the body portion 72 from the end edge of the body portion 72 on the side opposite to the bottom portion 71 in the axial direction. As shown in FIG. 4, the collar portion 73 is partially provided in the circumferential direction of the body portion 72, and a plurality of collar portions 73 having the same shape are arranged at equal intervals in the circumferential direction of the body portion 72. There are three locations. As shown in FIG. 3, the outward convex portion 74 protrudes outward in the radial direction from between the bottom portion 71 and the collar portion 73 in the axial direction of the body portion 72. As shown in FIG. 5, the outward convex portions 74 are partially provided in the circumferential direction of the body portion 72, and the outward convex portions 74 having the same shape are arranged at equal intervals in the circumferential direction of the body portion 72. There are multiple locations, specifically three locations. The outward convex portion 74 is located at a different position from the collar portion 73 in the circumferential direction of the body portion 72 . The outward convex portions 74 and the collar portions 73 are alternately arranged at equal intervals in the circumferential direction of the body portion 72.

The bumper cap 3 includes a plurality of fitting convex portions 91 having the same shape, specifically six locations, a plurality of abutment protrusions 92 (protrusions) having the same shape, and a plurality of contact protrusions 92 (protrusions) having the same shape. Specifically, it has three inclined protrusions 93 (protrusions) having the same shape. The fitting convex portion 91 is provided on the body portion 72 of the cover portion 75, and the abutting protrusion portion 92 and the inclined protrusion portion 93 are provided on the bottom portion 71 and the body portion 72 of the cover portion 75.

As shown in FIG. 4, the fitting convex portion 91 projects inward in the radial direction of the body 72 from the inner circumferential surface 72a of the body 72. As shown in FIG. The fitting convex portions 91 are partially provided in the circumferential direction of the body portion 72, and the fitting convex portions 91 having the same shape are provided at equal intervals in the circumferential direction of the body portion 72. Therefore, a gap is formed between the fitting convex portions 91 that are adjacent to each other in the circumferential direction of the body portion 72 .

The contact protrusion 92 protrudes from the inner surface 71a of the bottom portion 71 along the axial direction of the body portion 72 toward the opening 78 side. The inclined protrusion 93 also protrudes from the inner surface 71a of the bottom portion 71 toward the opening 78 side. The contact protrusions 92 and the inclined protrusions 93 are alternately arranged at equal intervals in the circumferential direction of the bottom part 71 and the body part 72. A gap is formed between the plurality of contact protrusions 92 and the plurality of inclined protrusions 93 that are adjacent to each other in the circumferential direction of the body section 72 . All of the abutting protrusions 92 and all of the inclined protrusions 93 are each connected to one location of the fitting convex portion 91 and the bottom portion 71 at a position in the circumferential direction.

The abutting protrusion 92 has a pair of side wall surfaces 92a and an inner wall surface 92b rising from the inner surface 71a of the bottom portion 71 along the axial direction of the body portion 72, and a pair of side wall surfaces 92a and an inner wall surface 92b of the body portion 72. It has an abutting surface 92c that connects and widens the end edge on the opposite side to the inner surface 71a in the axial direction.

The pair of side wall surfaces 92a are both planar and extend radially inward from the inner circumferential surface 72a of the body 72 along the radial direction of the body 72. The inner wall surface 92b connects the end edges of the pair of side wall surfaces 92a on the central axis side in the radial direction of the body portion 72. The inner wall surface 92b has the shape of a part of a cylindrical surface coaxial with the inner circumferential surface 72a of the body portion 72. The inner wall surfaces 92b of all the abutment protrusions 92 are shaped as part of the same cylindrical surface coaxial with the inner circumferential surface 72a of the body section 72. The contact surface 92c extends parallel to the inner surface 71a of the bottom portion 71. The fitting convex portion 91 extending from the abutting protrusion 92 extends toward the opening 78 along the axial direction of the body 72 from the center position of the abutment surface 92c in the circumferential direction of the body 72 .

The inclined protruding portion 93 has a contact portion 101 connected to the inner circumferential surface 72a of the body portion 72, and an inclined portion 102 (suppressing portion, fluid adjustment portion) protruding from the contact portion 101 toward the central axis of the body portion 72. have.

The contact portion 101 has a side wall surface 101a and a side wall surface 101b rising from the inner surface 71a of the bottom portion 71 along the axial direction of the body portion 72, and edges of the side wall surfaces 101a and 101b on the central axis side of the body portion 72. It has an inner wall surface 101c that connects together, and an abutment surface 101d that spreads out by connecting the side wall surfaces 101a, 101b and the end edges of the inner wall surface 101c on the side opposite to the inner surface 71a in the axial direction of the body section 72.

Both of the side wall surfaces 101a and 101b extend radially inward from the inner circumferential surface 72a of the body 72 substantially along the radial direction of the body 72. The side wall surface 101a has a planar shape at a side far from the central axis of the body 72 and extends in the radial direction of the body 72, and a side close to the central axis of the body 72 forms an inclined protrusion 93. It has the shape of a part of a cylindrical surface with a central axis on the outside of the cylinder. In the side wall surface 101b, a portion far from the central axis of the trunk 72 is planar and extends in the radial direction of the trunk 72, and a portion close to the central axis of the trunk 72 forms the inclined protrusion 93. It has the shape of a part of a cylindrical surface with a central axis line inside. The distance between the ends of the side wall surfaces 101a and 101b of the abutting portion 101 on the side far from the central axis of the body 72 is the distance between the ends of the side wall surfaces 92a of the pair of side wall surfaces 92a of the abutting protrusion 92 on the side far from the central axis of the body 72. It is equal to the distance between the ends.

The inner wall surface 101c has the shape of a part of a cylindrical surface coaxial with the inner circumferential surface 72a of the body portion 72. The inner wall surfaces 101c of all the contact portions 101 are shaped as part of the same cylindrical surface coaxial with the inner circumferential surface 72a of the body portion 72. The contact surface 101d extends parallel to the inner surface 71a. The height of the abutting surface 101d from the inner surface 71a of the bottom 71 is equal to the height of the abutting surface 92c of the abutting protrusion 92 from the inner surface 71a of the bottom 71. The fitting convex portion 91 extending from the inclined protrusion 93 extends from the center position of the contact surface 101d in the circumferential direction of the body 72 toward the opening 78 along the axial direction of the body 72.

The inclined portion 102 protrudes from the inner wall surface 101c of the contact portion 101 toward the central axis of the body portion 72. The inclined portion 102 includes an extended wall surface 102a and an inclined wall surface 102b rising from the inner surface 71a of the bottom portion 71 along the axial direction of the body portion 72, and an inner surface of the extended wall surface 102a and the inclined wall surface 102b in the axial direction of the body portion 72. It has a step surface 102c that extends by connecting an edge portion on the side opposite to 71a and an edge portion on the side opposite to the contact surface 101d of the inner wall surface 101c of the contact portion 101.

The extending wall surface 102a extends from the edge of the side wall surface 101a of the contact portion 101 on the central axis side of the body portion 72 toward the central axis side in a planar shape. As shown in FIG. 5, the extending wall surface 102a is located between the center position in the circumferential direction of the body portion 72 of the abutment portion 101 that constitutes the same inclined protrusion 93 as the inclined portion 102 on which it is formed. along the line connecting the axis.

The inclined wall surface 102b has a planar shape, and includes an edge portion on the side wall surface 101b of the contact portion 101 on the central axis side of the body portion 72, and an edge portion on the extended wall surface 102a on the central axis side of the body portion 72. are connected. As a result, the inclined wall surface 102b has a first end 111 that is the end on the side wall surface 101b side in the circumferential direction of the body 72 and a second end 111 that is the end on the extended wall surface 102a side in the circumferential direction of the body 72. The distance from the central axis of the body section 72 is longer than that of the end section 112. In other words, the inclined wall surface 102b is inclined with respect to the circumferential direction of the body portion 72 at the position of the inclined wall surface 102b. The stepped surface 102c extends substantially parallel to the inner surface 71a of the bottom portion 71. As shown in FIG. 4, the height of the stepped surface 102c of the inclined portion 102 from the inner surface 71a of the bottom portion 71 is slightly lower than the height of the abutting surface 101d of the abutting portion 101 from the inner surface 71a.

Here, as shown in FIG. 5, the three inclined protrusions 93 provided on the cover part 75 have the same shape and are arranged at equal intervals in the circumferential direction of the body part 72. Therefore, if the arrangement direction of the second end 112 with respect to the first end 111 of the inclined protrusion 93 at one location is one side in the circumferential direction of the body 72, all of the parts provided on the bumper cap 3 Regarding the inclined protrusion 93, the direction in which the second end 112 is arranged with respect to the first end 111 is on one side. As a result, in the bumper cap 3, the first ends 111 and the second ends 112 are arranged alternately in the circumferential direction of the bumper cap 3.

For this reason, the bumper cap 3 has a plurality of inclined protrusions 93 each having an inclined wall surface 102b formed thereon which faces toward the through hole 81 side of the cover part 75, that is, toward the inner diameter side and which is inclined in the same direction with respect to the circumferential direction of the cover part 75. have. In other words, the bumper cap 3 has a plurality of inclined protrusions 93 provided on the bottom portion 71, each having an inclined wall surface 102b that faces toward the inner diameter side of the bottom portion 71 and is inclined in the same direction with respect to the circumferential direction of the bottom portion 71. 102 is provided.

In the bumper cap 3, the through hole 81, all the fitting convex parts 91, all the abutting protrusions 92, and all the inclined protrusions 93 can be formed by a cutting die that moves in the axial direction of the body part 72. ing. Note that the inclined protrusion 93 may be formed separately from other parts of the bumper cap 3 and bonded to the other parts.

As shown in FIG. 2, the bumper cap 3 having such a configuration is constructed by inserting the rod 41 into the through hole 81 of the cover portion 75 and connecting one end of the cylinder 17 from which the rod 41 protrudes to the body portion 72. It is attached to the cylinder 17 by fitting on the inner circumferential side. At this time, the bumper cap 3 connects the outer tube 1 with the abutting surfaces 92c of the plurality of abutting projections 92 that protrude from the inner surface 71a of the bottom 71 of the cover 75 at intervals in the circumferential direction of the cover 75. It comes into contact with the locking part 36 of. Further, at this time, the bumper cap 3 also contacts the locking portion 36 of the outer cylinder 14 at the contact surface 101d of the contact portion 101 of the plurality of inclined protrusions 93 shown in FIG. Further, at this time, the bumper cap 3 is fixed to the cylinder 17 by fitting into the outer circumferential surface of the cylinder 17, that is, the outer circumferential surface of the side wall portion 21 of the outer cylinder 14 with all the fitting convex portions 91 shown in FIG. be done.

In the bumper cap 3 fixed to the cylinder 17 in this manner, as shown in FIG. 2, the cover portion 75 covers one end of the shock absorber body 2 from which the rod 41 of the cylinder 17 protrudes. Further, in the bumper cap 3 at this time, the circular through hole 81 is arranged coaxially with the cylindrical rod 41. In other words, the circular inner peripheral edge 82 including the inner peripheral end surface 82a, the tapered surface 82b, and the step surface 82c of the bottom portion 71 is arranged coaxially with the outer peripheral surface 41a of the circular rod 41. Therefore, as shown in FIG. and is constant at all positions in the circumferential direction of the rod 41.

As shown in FIG. 2, the lower end of the dust boot 65, which is one end in the axial direction, covers the outer periphery of the cover part 75 of the bumper cap 3 fixed to the cylinder 17, and covers all the flange parts of the cover part 75. It is fitted into the section 73 and fixed.

Patent Documents 1 and 2 disclose shock absorbers in which the end of the cylinder from which the rod protrudes is covered with a bumper cap. In the shock absorber described in Patent Document 2, a bellows-shaped dust boot extending from the vehicle body side covers the rod and bumper cap to suppress adhesion of dust and the like to the rod. Furthermore, Patent Document 2 discloses a structure in which the lower end of the dust boot is fixed to the bumper cap. If the lower end of the dust boot is fixed to the bumper cap in this manner, the opening at the lower end of the dust boot will be narrowed.

If the opening at the bottom of the dust boot is wide, the amount of entry of the cylinder into the dust boot increases during the shock absorber's retraction stroke, and when the air inside the dust boot is pushed out by the cylinder, this air will be pushed out from the opening at the bottom of the dust boot. It can be discharged well. Therefore, of the air discharged from inside the dust boot, only a small amount of air is discharged through the gap between the bumper cap and the cylinder.

In contrast, in the first embodiment, the lower end opening of the dust boot 65 is narrowed by fixing the lower end of the dust boot 65 to the flange 73 of the bumper cap 3, thereby preventing dust etc. from adhering to the rod 41. It is becoming more restrained. Therefore, of the air discharged from inside the dust boot 65, the amount of air discharged through the gap between the bumper cap 3 and the cylinder 17 increases. Therefore, in a bumper cap in which only a plurality of abutting protrusions 92 are arranged at equal intervals without providing the inclined protrusions 93 on the inner surface 71a of the bottom part 71, the abutting protrusions 92 in the circumferential direction of the through hole 81 of the bottom part 71 and Air flowing into the through hole 81 from a position between the abutting protrusions 92 and flowing between the abutting protrusions 92 is rotated vertically (in the axial direction and radial direction of the bumper cap). There is a possibility that a vortex (rotation within a plane arranged along a direction) is generated, which may generate an abnormal noise that is wind noise.

In the shock absorber 1 of the first embodiment, the plurality of inclined protrusions 93 provided on the bottom 71 of the cover part 75 of the bumper cap 3 are arranged in the same direction with respect to the circumferential direction of the bottom 71, facing toward the inner diameter side of the bottom 71. An inclined portion 102 having an inclined wall surface 102b that is inclined toward the lower end is provided. Therefore, a part of the air flowing from the outside of the cover part 75 through the through hole 81 between the inside of the cover part 75 and the shock absorber main body 2 is formed on the inclined wall surface 102b in the circumferential direction of the through hole 81. As shown by the two-dot chain arrow X1 in FIG. The flow passes through the gap and is discharged from the opening 78 of the cover part 75, and the flow flows along the circumferential direction of the bottom part 71 along the inner wall surface 92b of the abutting protrusion 92, as shown by the two-dot chain arrow X2 in FIG. It is divided into two parts. Then, the air flow along the inner wall surface 92b of the abutting protrusion 92 flows between the inclined protruding part 93 and the abutting protruding part 92 in the circumferential direction of the through hole 81, as shown by the two-dot chain arrow X3 in FIG. The air flows in from a position between the inclined protrusions 93 and the abutting protrusions 92 and collides with the vertically rotating vortex of the air that is about to flow between the inclined protrusions 93 and the abutting protrusions 92, thereby disturbing the vortices. Moreover, the plurality of inclined protrusions 93 provided on the bottom part 71 are provided with an inclined part 102 having an inclined wall surface 102b facing toward the inner diameter side of the bottom part 71 and inclined in the same direction with respect to the circumferential direction of the bottom part 71. . Thereby, it is possible to suppress the generation of abnormal noise due to the vortex of vertical rotation of air generated at all positions between the inclined protrusion 93 and the abutting protrusion 92 in the circumferential direction of the through hole 81.

That is, in the shock absorber 1, the inclined protruding portion 93 allows air, which is a fluid, to flow into the cover portion 75 from the outside of the cover portion 75 through the through hole 81 and between the inside of the cover portion 75 and the shock absorber body 2. Suppress rotation (vertical rotation) in . Thereby, generation of abnormal noise can be suppressed.

In addition, in the shock absorber 1, the air flow along the inclined wall surface 102b becomes a flow that spreads outward in the circumferential direction of the through hole 81, but the fluid velocity varies depending on the circumferential position of the through hole 81 due to the inclination of the inclined wall surface 102b. It will be different. This also causes turbulence in the air flow, which leads to suppressing the generation of abnormal noise.

That is, in the shock absorber 1, the inclined protruding portion 93 prevents the fluid spreading outward in the circumferential direction of the through hole 81 from the outside of the cover portion 75 through the through hole 81, regarding the air that is the fluid flowing into the inside of the cover portion 75. The speed is adjusted to vary depending on the circumferential position of the through hole 81. Thereby, generation of abnormal noise can be suppressed.

Moreover, in the shock absorber 1, the plurality of inclined protrusions 93 provided on the bottom part 71 are provided with an inclined part 102 having an inclined wall surface 102b that faces toward the inner diameter side of the bottom part 71 and is inclined in the same direction with respect to the circumferential direction of the bottom part 71. With a simple structure that includes only one, it is possible to suppress the generation of abnormal noise.

In addition, in the shock absorber 1, the outer periphery of the cover portion 75 is covered by the dust boot 65 that covers at least a portion of the rod 41, and the cover portion 75 is fixed to one end of the dust boot 65, so that the dust boot 65 covers at least a portion of the rod 41. The adhesion of dust, etc. can be suppressed. Further, a cover part 75 is fixed to one end of the dust boot 65, and a large flow rate of air flows from the outside of the cover part 75 through the through hole 81 and between the inside of the cover part 75 and the shock absorber main body 2. Because of this structure, there is a high possibility that abnormal noise will occur. Therefore, there is a high need to suppress abnormal noise.

In the bumper cap 3, the through hole 81, all the fitting convex parts 91, all the abutting protrusions 92, and all the inclined protrusions 93 can be formed by a cutting die that moves in the axial direction of the body part 72. Therefore, these can be easily formed. Therefore, generation of abnormal noise can be easily suppressed.

Since the bumper cap 3 can suppress the generation of abnormal noise with its own structure and does not involve changing the shock absorber main body 2, the bumper cap 3 can easily suppress the generation of abnormal noise.

[Second embodiment]
A second embodiment according to the present invention will be described mainly based on FIG. 6, focusing on the differences from the first embodiment. Note that parts common to those in the first embodiment are denoted by the same names and symbols.

In the second embodiment, as shown in FIG. 6, a bumper cap 3A that is partially different from the bumper cap 3 of the first embodiment is used instead of the bumper cap 3 of the first embodiment.

The bumper cap 3A is also an integrally molded product made of synthetic resin. In the bumper cap 3A, a cover portion 75A is partially different from the cover portion 75 of the first embodiment, and specifically, a bottom portion 71A is partially different from the bottom portion 71.

The bottom portion 71A has a holed disk shape, and a through hole 81A that penetrates in the axial direction is formed at the center in the radial direction. The through hole 81A is an irregularly shaped hole whose cross section in a plane perpendicular to its central axis is not circular. In other words, the inner peripheral edge 82A of the bottom 71A forming the through hole 81A has an irregular shape that is not circular. Therefore, the bottom portion 71A has an inner surface 71Aa which has a different shape at the through hole 81A from the inner surface 71a.

The inner circumferential edge portion 82A of the bottom portion 71A has a plurality of arcuate portions, specifically three arcuate portions 121 (suppressing portions, fluid adjustment portions) whose centers are farther from the center of the bottom portion 71A. These arcuate portions 121 are all circular arcs with the same diameter, and are arranged at equal intervals in the circumferential direction of the bottom portion 71A. That is, the arcuate portion 121 has an inner end surface 121a forming the through hole 81A in an arcuate shape with its center located on a side farther from the center of the bottom portion 71A. The inner end surfaces 121a of the three arcuate portions 121 are all arcuate with the same diameter, are located at equal distances from the center of the bottom portion 71A, and are arranged at equal intervals in the circumferential direction of the bottom portion 71A. .

Moreover, the bumper cap 3A has an abutting protrusion 92 formed therein instead of the inclined protrusion 93 of the first embodiment. That is, the bumper cap 3A has a plurality of abutment protrusions 92, specifically six, having the same shape. These abutting projections 92 are provided on the bottom 71A and the body 72 of the cover 75A. These contact protrusions 92 are arranged at equal intervals in the circumferential direction of the bottom portion 71A and the body portion 72. A gap is formed between these abutting protrusions 92 that are adjacent to each other in the circumferential direction of the body 72 .

The number of abutting protrusions 92 is twice the number of arcuate portions 121. In the circumferential direction of the bottom portion 71A, the center position of the arcuate portion 121 and the center position between the adjacent abutting protrusions 92 are aligned. Furthermore, the boundary position between the adjacent arcuate portions 121 and the center position between the adjacent abutment protrusions 92 are aligned.

Also in the bumper cap 3A, the through hole 81A, all the fitting convex portions 91, and all the abutting protrusions 92 can be formed by a cutting die that moves in the axial direction of the body portion 72.

In the bumper cap 3A having such a configuration, the rod 41 is inserted into the through hole 81A of the cover portion 75A, and one end of the cylinder 17 on the side from which the rod 41 protrudes is fitted into the inner peripheral side of the body portion 72. As a result, it is attached to the cylinder 17. At this time, the bumper cap 3A connects the outer cylinder 10 with the abutting surfaces 92c of the plurality of abutting protrusions 92 that protrude from the inner surface 71Aa of the bottom 71A of the cover 75A at intervals in the circumferential direction of the cover 75A. It comes into contact with the locking part 36 of. Further, at this time, the bumper cap 3A is fixed to the cylinder 17 by fitting all the fitting convex portions 91 to the outer circumferential surface of the cylinder 17, that is, the outer circumferential surface of the side wall portion 21 of the outer cylinder 14.

In the bumper cap 3A fixed to the cylinder 17 in this manner, the cover portion 75A covers one end side of the cylinder 17 of the shock absorber body 2 from which the rod 41 protrudes. Further, in the bumper cap 3A at this time, the through hole 81A of the irregularly shaped hole is arranged coaxially with the cylindrical rod 41. In other words, the inner peripheral edge 82A of the bottom 71A, which is provided in the bottom 71A of the cover part 75A and forms the through hole 81A, is arranged coaxially with the outer peripheral surface 41a of the circular rod 41.

Since the inner circumferential edge 82A of the bottom portion 71A is composed of a plurality of arcuate parts 121, the inner circumferential edge 82A serves as a flow path for air when it enters between the bumper cap 3A and the shock absorber main body 2. The radial distance between the inner end surface 121a of the arcuate portion 121 and the outer circumferential surface 41a of the rod 41 differs depending on the circumferential position of the bottom portion 71A.

That is, in the circumferential direction of the bottom portion 71A and the rod 41, the radial distance between the inner end surface 121a and the outer circumferential surface 41a is the shortest at the center position of the inner end surface 121a of the arcuate portion 121, and the farther from this center position, the shorter the radial distance is. , the radial distance between the inner end surface 121a and the outer peripheral surface 41a becomes longer, and the radial distance between the inner end surface 121a and the outer peripheral surface 41a becomes the longest at the end position of the inner end surface 121a.

In this way, the plurality of arcuate portions 121 of the inner circumferential edge portion 82A forming the through hole 81A of the bottom portion 71A of the cover portion 75A are formed such that the distance from the rod 41 varies depending on the circumferential position.

In the second embodiment, the inner peripheral edge 82A forming the through hole 81A of the bottom 71A of the cover portion 75A is formed by a plurality of arcuate portions 121 so that the distance from the rod 41 varies depending on the circumferential position. Therefore, the fluid velocity of air flowing from the outside of the cover portion 75A through the through hole 81A between the inside of the cover portion 75A and the shock absorber body 2 varies depending on the circumferential position of the through hole 81A. Become. That is, the flow velocity is slow at the end position of the inner end surface 121a where the radial distance between the inner end surface 121a and the outer peripheral surface 41a is the longest, and the flow velocity is the lowest at the end position of the inner end surface 121a where the radial distance between the inner end surface 121a and the outer peripheral surface 41a is the longest. The flow velocity is high at the center position of the short inner end surface 121a. In other words, the plurality of arcuate parts 121 of the inner circumferential edge 82A forming the through hole 81A of the bottom 71A of the cover part 75A allow fluid to flow into the inside of the cover part 75A from the outside of the cover part 75A through the through hole 81A. With respect to the air, the velocity of the fluid that spreads outward in the circumferential direction of the through hole 81A is adjusted so as to vary depending on the circumferential position of the through hole 81A. Thereby, generation of abnormal noise can be suppressed.

Furthermore, the generation of abnormal noise can be suppressed with a simple structure in which the inner peripheral edge 82A forming the through hole 81A of the bottom 71A of the cover part 75A is formed so that the distance from the rod 41 varies depending on the circumferential position. I can do it.

In the bumper cap 3A, the through hole 81A, all the fitting convex portions 91, and all the abutting protrusions 92 can be formed by a cutting die that moves in the axial direction of the body portion 72, so these can be easily formed. can be formed into Therefore, generation of abnormal noise can be easily suppressed.

The bumper cap 3A can suppress the generation of abnormal noise with its own structure and does not involve changing the shock absorber main body 2, so that the generation of abnormal noise can be easily suppressed.

The bumper cap of the first aspect of the embodiment described above is a bumper cap that is attached to the shock absorber main body, and has an opening at one end and a bottom and a through hole passing through the bottom at the other end. The cover includes a cover portion that covers the shock absorber main body, and a plurality of protrusion portions that protrude from the bottom portion of the cover portion toward the opening side and have gaps formed between adjacent ones. A suppressing portion is provided for suppressing rotation within the cover portion of fluid flowing from the outside of the portion through the through hole and flowing between the inside of the cover portion and the shock absorber main body. Thereby, generation of abnormal noise can be suppressed.

The bumper cap of the second aspect of the embodiment is the bumper cap of the first aspect, wherein the rod of the shock absorber main body is inserted into the through hole, and the suppressing part forms the through hole of the bottom part. The rod is provided at an inner peripheral edge of the bottom portion, and the distance between the rod and the inner peripheral edge of the bottom portion is formed to vary depending on the circumferential position.

A bumper cap according to a third aspect of the embodiment is a bumper cap that is attached to a shock absorber main body, and has an opening at one end and a bottom and a through hole passing through the bottom at the other end. A cover part that covers the main body of the container, and a plurality of protrusion parts that protrude from the bottom part of the cover part toward the opening side and have gaps between adjacent ones, and are provided in the bottom part. The plurality of protrusions are provided with inclined portions that face toward the inner diameter side of the bottom portion and are inclined in the same direction with respect to the circumferential direction of the bottom portion. Thereby, generation of abnormal noise can be suppressed.

A shock absorber according to a fourth aspect of the embodiment is a shock absorber having a cylinder and a rod extending from one end side of the cylinder, and a through hole through which the rod is inserted is formed, and the one end side of the cylinder is formed with a through hole through which the rod is inserted. a cover portion to cover, a plurality of protruding portions protruding from the inner surface of the cover portion at intervals in the circumferential direction of the cover portion, and flow from the outside of the cover portion through the through hole and into the inside of the cover portion. and a fluid adjustment unit that adjusts the velocity of the fluid that spreads outward in the circumferential direction of the through hole so that it varies depending on the circumferential position of the through hole. Thereby, generation of abnormal noise can be suppressed.

A shock absorber according to a fifth aspect of the embodiment is the shock absorber according to the fourth aspect, in which the fluid adjustment section is provided at an inner peripheral edge forming the through hole of the bottom, and the rod and the bottom The distance from the inner circumferential edge portion to the inner circumferential edge portion is formed to vary depending on the circumferential position.

A shock absorber according to a sixth aspect of the embodiment is the shock absorber according to the fourth aspect, wherein the fluid adjustment section is provided in the cover section, and the fluid adjustment section is arranged in the circumferential direction of the cover section toward the inner diameter side of the cover section. It has a plurality of inclined protrusions that are inclined in the same direction relative to each other.

A shock absorber according to a seventh aspect of the embodiment is the shock absorber according to the fourth to sixth aspects, and the outer periphery of the cover portion is covered with a dust boot that covers at least a portion of the rod, and the cover portion is Fixed.

According to the bumper cap and shock absorber according to each of the above aspects of the present invention, it is possible to suppress the generation of abnormal noise.

1 Buffer 2 Buffer body 3, 3A Bumper cap 17 Cylinder 41 Rod 65 Dust boot 71, 71A Bottom 71a, 71Aa Inner surface 75, 75A Cover portion 78 Opening 81, 81A Through hole 82, 82A Inner peripheral edge 92 Contact protrusion (protrusion)
93 Inclined protrusion (protrusion)
102 Inclined part (suppression part, fluid adjustment part)
121 Arc-shaped part (suppression part, fluid adjustment part)

Claims (7)

It is a bumper cap attached to the shock absorber body,
a cover portion having an opening at one end and a bottom portion and a through hole passing through the bottom portion at the other end to cover the shock absorber main body;
a plurality of protrusions that protrude from the bottom of the cover part toward the opening side, and a gap is formed between adjacent protrusions;
A bumper cap provided with a suppressing portion that suppresses rotation within the cover portion of fluid flowing from the outside of the cover portion through the through hole and flowing between the inside of the cover portion and the shock absorber main body. The bumper cap according to claim 1,
A rod of the shock absorber main body is inserted into the through hole,
The suppressing portion is provided at an inner circumferential edge of the bottom that forms the through hole, and the bumper cap is formed such that a distance between the rod and the inner circumferential edge of the bottom varies depending on a circumferential position. It is a bumper cap attached to the shock absorber body,
a cover portion having an opening at one end and a bottom portion and a through hole passing through the bottom portion at the other end to cover the shock absorber main body;
a plurality of protrusions that protrude from the bottom of the cover part toward the opening side, and a gap is formed between adjacent protrusions;
In the bumper cap, the plurality of protrusions provided on the bottom portion are provided with inclined portions that face toward the inner diameter side of the bottom portion and are inclined in the same direction with respect to the circumferential direction of the bottom portion. A shock absorber including a cylinder and a rod extending from one end of the cylinder,
a cover portion having a through hole through which the rod is inserted and covering one end side of the cylinder; a plurality of protruding portions protruding from an inner surface of the cover portion at intervals in a circumferential direction of the cover portion;
A fluid that adjusts a fluid flowing from the outside of the cover part through the through hole and into the inside of the cover part so that the velocity of the fluid spreading outward in the circumferential direction of the through hole varies depending on the circumferential position of the through hole. an adjustment section;
A buffer equipped with. The buffer according to claim 4,
The fluid adjustment section is provided at an inner circumferential edge of the cover section that forms the through hole, and the buffer is formed such that the distance between the rod and the inner circumferential edge of the cover section varies depending on the position in the circumferential direction. vessel. The buffer according to claim 4,
The fluid adjustment section is a shock absorber having a plurality of inclined protrusions that are provided on the cover section and are inclined toward the inner diameter side of the cover section and in the same direction with respect to the circumferential direction of the cover section. The buffer according to any one of claims 4 to 6,
A shock absorber, wherein an outer periphery of the cover part is covered and the cover part is fixed to a dust boot that covers at least a part of the rod.

Images